Optical demultiplexer, optical separation device, optical transmission system, and optical transmission method

Abstract

An optical demultiplexer 40 includes: a plurality of optical gate switches 41a to 41n configured to transmit, when being turned on, and to block, when being turned off, a multiplexed optical signal obtained by multiplexing optical signals of a plurality of wavelengths by time-division multiplexing or wavelength-division multiplexing in addition to time-division multiplexing; and a cAWG 42 including a plurality of input ports and a plurality of output ports and configured to input the multiplexed optical signal transmitted through the optical gate switches 41a to 41n from the plurality of input ports, demultiplex the input multiplexed optical signal for each wavelength, and cycle and output the demultiplexed optical signals from the plurality of output ports in a predetermined order.

The invention claimed is: 
     
       1. An optical demultiplexer, comprising:
 a plurality of optical gate switches, each of which is configured to transmit, when being turned on, and to block, when being turned off, a multiplexed optical signal received from one optical coupler,
 the multiplexed optical signal being obtained by multiplexing optical signals of a plurality of wavelengths by time-division multiplexing or multiplexing optical signals of a plurality of wavelengths by wavelength-division multiplexing in addition to time-division multiplexing; and 
 
 a cyclic arrayed waveguide grating (cAWG) including a plurality of input ports and a plurality of output ports and configured to input the multiplexed optical signal transmitted through the plurality of optical gate switches from the plurality of input ports, demultiplex the input multiplexed optical signal for each wavelength, and cycle and output the demultiplexed optical signals from the plurality of output ports in a predetermined order. 
 
     
     
       2. An optical separator, comprising:
 a plurality of optical gate switches, each of which is configured to perform i) an on operation for transmitting an optical signal of a predetermined single wavelength in a predetermined time slot and ii) an off operation for blocking an optical signal,
 each of the plurality of optical gate switches performing, when a multiplexed optical signal obtained by multiplexing optical signals of a plurality of wavelengths by time-division multiplexing is input, the on operation during a corresponding predetermined time slot when the time-division multiplexing is performed, to separate an optical signal of a corresponding single wavelength stored in the corresponding predetermined time slot; and 
 
 a cAWG including a plurality of input ports and a plurality of output ports and configured to input the optical signal of the predetermined single wavelength transmitted through the plurality of optical gate switches from the plurality of input ports, and cycle and output the input optical signal of the predetermined single wavelength from the plurality of output ports in a predetermined order. 
 
     
     
       3. The optical separator according to  claim 2 , wherein
 when the multiplexed optical signal obtained by multiplexing optical signals of a plurality of wavelengths by wavelength-division multiplexing in addition to the time-division multiplexing is input, each of the plurality of optical gate switches performs the on operation during the corresponding predetermined time slot when the time-division multiplexing is performed, to separate an optical signal of the corresponding single wavelength stored in the corresponding predetermined time slot, and 
 the cAWG inputs the optical signal of the predetermined single wavelength transmitted through the optical gate switches from the plurality of input ports, demultiplexes the input optical signal of the predetermined single wavelength, and cycles and outputs the demultiplexed optical signals from the plurality of output ports in a predetermined order. 
 
     
     
       4. An optical transmission system, comprising:
 a plurality of transmission nodes configured to transmit optical signals of a plurality of wavelengths; 
 one optical coupler configured to multiplex the optical signals of a plurality of wavelengths transmitted from the plurality of transmission nodes by time-division multiplexing or wavelength-division multiplexing in addition to time-division multiplexing; 
 a second optical coupler connected to the one optical coupler via an optical transmission line and configured to branch the multiplexed optical signal transmitted in the optical transmission line; and 
 a plurality of reception nodes connected to the optical demultiplexer described in  claim 1  to which the second optical coupler is connected, wherein 
 the multiplexed optical signal branched by the second optical coupler is transmitted through each of the optical gate switches of the optical demultiplexer and optical signals obtained by demultiplexing the transmitted multiplexed optical signal for each wavelength by the optical demultiplexer are received at the reception nodes. 
 
     
     
       5. An optical transmission system, comprising:
 an optical transmission line having a ring shape; 
 a first optical coupler connected to the optical transmission line and configured to multiplex optical signals of a plurality of wavelengths by time-division multiplexing or wavelength-division multiplexing in addition to time-division multiplexing, thereby generating a multiplexed optical signal; 
 a second optical coupler connected to the optical transmission line and configured to branch the multiplexed optical signal multiplexed by the first optical coupler; 
 a first node connected to the first optical coupler and having a plurality of optical transmitters configured to transmit optical signals of a plurality of wavelengths; and 
 a second node having the optical demultiplexer described in  claim 1  connected to the second optical coupler and a plurality of optical receivers configured to receive optical signals from the plurality of optical transmitters via the optical demultiplexer, wherein 
 optical signals of a plurality of wavelengths transmitted from the plurality of optical transmitters are multiplexed by the first optical coupler, the multiplexed optical signal is transmitted through each of the optical gate switches of the optical demultiplexer, and optical signals obtained by demultiplexing the transmitted multiplexed optical signal for each wavelength by the optical demultiplexer are received by the optical receivers. 
 
     
     
       6. An optical transmission system, comprising:
 a plurality of transmission nodes configured to transmit optical signals of a plurality of wavelengths; 
 one optical coupler configured to transmit a multiplexed optical signal obtained by multiplexing the optical signals of a plurality of wavelengths transmitted from the plurality of transmission nodes by time-division multiplexing; 
 a second optical coupler connected to the one optical coupler via an optical transmission line and configured to branch the multiplexed optical signal transmitted in the optical transmission line; and 
 a plurality of reception nodes connected to the optical separator described in  claim 2  to which the second optical coupler is connected, wherein 
 the multiplexed optical signal branched by the second optical coupler is transmitted through each of the optical gate switches of the optical separator, and optical signals obtained by separating the transmitted multiplexed optical signal for each time slot in the optical separator are received at the plurality of reception nodes. 
 
     
     
       7. An optical transmission system, comprising:
 a plurality of transmission nodes configured to transmit optical signals of a plurality of wavelengths; 
 one optical coupler configured to transmit a multiplexed optical signal obtained by multiplexing the optical signals of a plurality of wavelengths transmitted from the plurality of transmission nodes by wavelength-division multiplexing in addition to time-division multiplexing; 
 a second optical coupler connected to the one optical coupler via an optical transmission line and configured to branch the multiplexed optical signal transmitted in the optical transmission line; and 
 a plurality of reception nodes connected to the optical separator described in  claim 3  to which the second optical coupler is connected, wherein 
 the multiplexed optical signal branched by the second optical coupler is transmitted through each of the optical gate switches of the optical separator, and optical signals obtained by demultiplexing the transmitted multiplexed optical signal for each time slot in the optical separator are received at the plurality of reception nodes. 
 
     
     
       8. An optical transmission method of an optical transmission system, the method comprising:
 transmitting optical signals of a plurality of wavelengths from a plurality of transmission nodes; 
 multiplexing the transmitted optical signals of a plurality of wavelengths by time-division multiplexing or wavelength-division multiplexing in addition to time-division multiplexing by one optical coupler; 
 transmitting the multiplexed optical signal to a second optical coupler via an optical transmission line; 
 branching the transmitted multiplexed optical signal by the second optical coupler; and 
 receiving optical signals obtained by the branching by a plurality of reception nodes, wherein 
 an optical demultiplexer for demultiplexing the multiplexed optical signal transmitted in the optical transmission line for each wavelength is provided for the plurality of reception nodes, 
 the optical demultiplexer performs:
 transmitting or blocking the multiplexed optical signal transmitted in the optical transmission line; and 
 demultiplexing the transmitted multiplexed optical signal for each wavelength, and cycling and delivering optical signals obtained by the demultiplexing to the plurality of reception nodes in a predetermined order.